2 * ==FILEVERSION 970428==
4 * ppp_deflate.c - interface the zlib procedures for Deflate compression
5 * and decompression (as used by gzip) to the PPP code.
6 * This version is for use with Linux kernel 1.3.X.
8 * Copyright (c) 1994 The Australian National University.
11 * Permission to use, copy, modify, and distribute this software and its
12 * documentation is hereby granted, provided that the above copyright
13 * notice appears in all copies. This software is provided without any
14 * warranty, express or implied. The Australian National University
15 * makes no representations about the suitability of this software for
18 * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
19 * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
20 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
21 * THE AUSTRALIAN NATIONAL UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY
24 * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
25 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
26 * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
27 * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
28 * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
31 * From: deflate.c,v 1.1 1996/01/18 03:17:48 paulus Exp
34 #include <linux/module.h>
36 #include <linux/kernel.h>
37 #include <linux/sched.h>
38 #include <linux/types.h>
39 #include <linux/fcntl.h>
40 #include <linux/interrupt.h>
41 #include <linux/ptrace.h>
42 #include <linux/ioport.h>
44 #include <linux/malloc.h>
45 #include <linux/vmalloc.h>
46 #include <linux/errno.h>
47 #include <linux/sched.h> /* to get the struct task_struct */
48 #include <linux/string.h> /* used in new tty drivers */
49 #include <linux/signal.h> /* used in new tty drivers */
51 #include <asm/system.h>
53 #include <linux/netdevice.h>
54 #include <linux/skbuff.h>
55 #include <linux/inet.h>
56 #include <linux/ioctl.h>
58 #include <linux/ppp_defs.h>
59 #include <linux/ppp-comp.h>
64 * State for a Deflate (de)compressor.
66 struct ppp_deflate_state {
73 struct compstat stats;
76 #define DEFLATE_OVHD 2 /* Deflate overhead/packet */
78 static void *zalloc __P((void *, unsigned int items, unsigned int size));
79 static void *zalloc_init __P((void *, unsigned int items,
81 static void zfree __P((void *, void *ptr, unsigned int nb));
82 static void *z_comp_alloc __P((unsigned char *options, int opt_len));
83 static void *z_decomp_alloc __P((unsigned char *options, int opt_len));
84 static void z_comp_free __P((void *state));
85 static void z_decomp_free __P((void *state));
86 static int z_comp_init __P((void *state, unsigned char *options,
88 int unit, int hdrlen, int debug));
89 static int z_decomp_init __P((void *state, unsigned char *options,
91 int unit, int hdrlen, int mru, int debug));
92 static int z_compress __P((void *state, unsigned char *rptr,
94 int isize, int osize));
95 static void z_incomp __P((void *state, unsigned char *ibuf, int icnt));
96 static int z_decompress __P((void *state, unsigned char *ibuf,
97 int isize, unsigned char *obuf, int osize));
98 static void z_comp_reset __P((void *state));
99 static void z_decomp_reset __P((void *state));
100 static void z_comp_stats __P((void *state, struct compstat *stats));
102 struct chunk_header {
103 unsigned size; /* amount of space following header */
104 int valloced; /* allocated with valloc, not kmalloc */
107 #define MIN_VMALLOC 2048 /* use kmalloc for blocks < this */
110 * Space allocation and freeing routines for use by zlib routines.
113 zfree(arg, ptr, nbytes)
118 struct chunk_header *hdr = ((struct chunk_header *)ptr) - 1;
127 zalloc(arg, items, size)
129 unsigned int items, size;
131 struct chunk_header *hdr;
134 nbytes = items * size + sizeof(*hdr);
135 hdr = kmalloc(nbytes, GFP_ATOMIC);
140 return (void *) (hdr + 1);
144 zalloc_init(arg, items, size)
146 unsigned int items, size;
148 struct chunk_header *hdr;
151 nbytes = items * size + sizeof(*hdr);
152 if (nbytes >= MIN_VMALLOC)
153 hdr = vmalloc(nbytes);
155 hdr = kmalloc(nbytes, GFP_KERNEL);
159 hdr->valloced = nbytes >= MIN_VMALLOC;
160 return (void *) (hdr + 1);
167 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
170 deflateEnd(&state->strm);
177 * Allocate space for a compressor.
180 z_comp_alloc(options, opt_len)
181 unsigned char *options;
184 struct ppp_deflate_state *state;
187 if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE
188 || options[1] != CILEN_DEFLATE
189 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
190 || options[3] != DEFLATE_CHK_SEQUENCE)
192 w_size = DEFLATE_SIZE(options[2]);
193 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
196 state = (struct ppp_deflate_state *) kmalloc(sizeof(*state), GFP_KERNEL);
201 memset (state, 0, sizeof (struct ppp_deflate_state));
202 state->strm.next_in = NULL;
203 state->strm.zalloc = zalloc;
204 state->strm.zalloc_init = zalloc;
205 state->strm.zfree = zfree;
206 state->w_size = w_size;
208 if (deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION, DEFLATE_METHOD_VAL,
209 -w_size, 8, Z_DEFAULT_STRATEGY, DEFLATE_OVHD+2) != Z_OK) {
213 return (void *) state;
217 z_comp_init(arg, options, opt_len, unit, hdrlen, debug)
219 unsigned char *options;
220 int opt_len, unit, hdrlen, debug;
222 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
224 if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
225 || options[1] != CILEN_DEFLATE
226 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
227 || DEFLATE_SIZE(options[2]) != state->w_size
228 || options[3] != DEFLATE_CHK_SEQUENCE)
233 state->debug = debug;
235 deflateReset(&state->strm);
244 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
247 deflateReset(&state->strm);
251 z_compress(arg, rptr, obuf, isize, osize)
253 unsigned char *rptr; /* uncompressed packet (in) */
254 unsigned char *obuf; /* compressed packet (out) */
257 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
258 int r, proto, off, olen;
262 * Check that the protocol is in the range we handle.
264 proto = PPP_PROTOCOL(rptr);
265 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
268 /* Don't generate compressed packets which are larger than
269 the uncompressed packet. */
276 * Copy over the PPP header and store the 2-byte sequence number.
278 wptr[0] = PPP_ADDRESS(rptr);
279 wptr[1] = PPP_CONTROL(rptr);
280 wptr[2] = PPP_COMP >> 8;
283 wptr[0] = state->seqno >> 8;
284 wptr[1] = state->seqno;
286 state->strm.next_out = wptr;
287 state->strm.avail_out = osize - (PPP_HDRLEN + 2);
290 off = (proto > 0xff) ? 2 : 3; /* skip 1st proto byte if 0 */
292 state->strm.next_in = rptr;
293 state->strm.avail_in = (isize - off);
297 r = deflate(&state->strm, Z_PACKET_FLUSH);
300 printk(KERN_DEBUG "z_compress: deflate returned %d (%s)\n",
301 r, (state->strm.msg? state->strm.msg: ""));
304 if (state->strm.avail_out == 0) {
306 state->strm.next_out = NULL;
307 state->strm.avail_out = 1000000;
309 break; /* all done */
313 olen += osize - state->strm.avail_out;
316 * See if we managed to reduce the size of the packet.
317 * If the compressor just gave us a single zero byte, it means
318 * the packet was incompressible.
320 if (olen < isize && !(olen == PPP_HDRLEN + 3 && *wptr == 0)) {
321 state->stats.comp_bytes += olen;
322 state->stats.comp_packets++;
324 state->stats.inc_bytes += isize;
325 state->stats.inc_packets++;
328 state->stats.unc_bytes += isize;
329 state->stats.unc_packets++;
335 z_comp_stats(arg, stats)
337 struct compstat *stats;
339 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
341 *stats = state->stats;
348 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
351 inflateEnd(&state->strm);
353 memPoolFree(&state->strm.opaque);
361 * Allocate space for a decompressor.
364 z_decomp_alloc(options, opt_len)
365 unsigned char *options;
368 struct ppp_deflate_state *state;
371 if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE
372 || options[1] != CILEN_DEFLATE
373 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
374 || options[3] != DEFLATE_CHK_SEQUENCE)
376 w_size = DEFLATE_SIZE(options[2]);
377 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
380 state = (struct ppp_deflate_state *) kmalloc(sizeof(*state), GFP_KERNEL);
385 memset (state, 0, sizeof (struct ppp_deflate_state));
386 state->w_size = w_size;
387 state->strm.next_out = NULL;
388 state->strm.zalloc = zalloc;
389 state->strm.zfree = zfree;
391 if (inflateInit2(&state->strm, -w_size) != Z_OK) {
392 z_decomp_free(state);
395 return (void *) state;
399 z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug)
401 unsigned char *options;
402 int opt_len, unit, hdrlen, mru, debug;
404 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
406 if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
407 || options[1] != CILEN_DEFLATE
408 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
409 || DEFLATE_SIZE(options[2]) != state->w_size
410 || options[3] != DEFLATE_CHK_SEQUENCE)
415 state->debug = debug;
418 inflateReset(&state->strm);
427 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
430 inflateReset(&state->strm);
434 * Decompress a Deflate-compressed packet.
436 * Because of patent problems, we return DECOMP_ERROR for errors
437 * found by inspecting the input data and for system problems, but
438 * DECOMP_FATALERROR for any errors which could possibly be said to
439 * be being detected "after" decompression. For DECOMP_ERROR,
440 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
441 * infringing a patent of Motorola's if we do, so we take CCP down
444 * Given that the frame has the correct sequence number and a good FCS,
445 * errors such as invalid codes in the input most likely indicate a
446 * bug, so we return DECOMP_FATALERROR for them in order to turn off
447 * compression, even though they are detected by inspecting the input.
450 z_decompress(arg, ibuf, isize, obuf, osize)
457 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
459 int decode_proto, overflow;
460 unsigned char overflow_buf[1];
462 if (isize <= PPP_HDRLEN + DEFLATE_OVHD) {
464 printk(KERN_DEBUG "z_decompress%d: short packet (len=%d)\n",
469 /* Check the sequence number. */
470 seq = (ibuf[PPP_HDRLEN] << 8) + ibuf[PPP_HDRLEN+1];
471 if (seq != state->seqno) {
473 printk(KERN_DEBUG "z_decompress%d: bad seq # %d, expected %d\n",
474 state->unit, seq, state->seqno);
480 * Fill in the first part of the PPP header. The protocol field
481 * comes from the decompressed data.
483 obuf[0] = PPP_ADDRESS(ibuf);
484 obuf[1] = PPP_CONTROL(ibuf);
488 * Set up to call inflate. We set avail_out to 1 initially so we can
489 * look at the first byte of the output and decide whether we have
490 * a 1-byte or 2-byte protocol field.
492 state->strm.next_in = ibuf + PPP_HDRLEN + DEFLATE_OVHD;
493 state->strm.avail_in = isize - (PPP_HDRLEN + DEFLATE_OVHD);
494 state->strm.next_out = obuf + 3;
495 state->strm.avail_out = 1;
500 * Call inflate, supplying more input or output as needed.
503 r = inflate(&state->strm, Z_PACKET_FLUSH);
506 printk(KERN_DEBUG "z_decompress%d: inflate returned %d (%s)\n",
507 state->unit, r, (state->strm.msg? state->strm.msg: ""));
508 return DECOMP_FATALERROR;
510 if (state->strm.avail_out != 0)
511 break; /* all done */
513 state->strm.avail_out = osize - PPP_HDRLEN;
514 if ((obuf[3] & 1) == 0) {
515 /* 2-byte protocol field */
517 --state->strm.next_out;
518 ++state->strm.avail_out;
521 } else if (!overflow) {
523 * We've filled up the output buffer; the only way to
524 * find out whether inflate has any more characters left
525 * is to give it another byte of output space.
527 state->strm.next_out = overflow_buf;
528 state->strm.avail_out = 1;
532 printk(KERN_DEBUG "z_decompress%d: ran out of mru\n",
534 return DECOMP_FATALERROR;
541 olen = osize + overflow - state->strm.avail_out;
542 state->stats.unc_bytes += olen;
543 state->stats.unc_packets++;
544 state->stats.comp_bytes += isize;
545 state->stats.comp_packets++;
551 * Incompressible data has arrived - add it to the history.
554 z_incomp(arg, ibuf, icnt)
559 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
563 * Check that the protocol is one we handle.
565 proto = PPP_PROTOCOL(ibuf);
566 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
572 * Iterate through the message blocks, adding the characters in them
573 * to the decompressor's history. For the first block, we start
574 * at the either the 1st or 2nd byte of the protocol field,
575 * depending on whether the protocol value is compressible.
577 state->strm.next_in = ibuf + 3;
578 state->strm.avail_in = icnt - 3;
580 --state->strm.next_in;
581 ++state->strm.avail_in;
584 r = inflateIncomp(&state->strm);
588 printk(KERN_DEBUG "z_incomp%d: inflateIncomp returned %d (%s)\n",
589 state->unit, r, (state->strm.msg? state->strm.msg: ""));
597 state->stats.inc_bytes += icnt;
598 state->stats.inc_packets++;
599 state->stats.unc_bytes += icnt;
600 state->stats.unc_packets++;
603 /*************************************************************
604 * Module interface table
605 *************************************************************/
607 /* These are in ppp.c */
608 extern int ppp_register_compressor (struct compressor *cp);
609 extern void ppp_unregister_compressor (struct compressor *cp);
612 * Procedures exported to if_ppp.c.
614 struct compressor ppp_deflate = {
615 CI_DEFLATE, /* compress_proto */
616 z_comp_alloc, /* comp_alloc */
617 z_comp_free, /* comp_free */
618 z_comp_init, /* comp_init */
619 z_comp_reset, /* comp_reset */
620 z_compress, /* compress */
621 z_comp_stats, /* comp_stat */
622 z_decomp_alloc, /* decomp_alloc */
623 z_decomp_free, /* decomp_free */
624 z_decomp_init, /* decomp_init */
625 z_decomp_reset, /* decomp_reset */
626 z_decompress, /* decompress */
627 z_incomp, /* incomp */
628 z_comp_stats, /* decomp_stat */
632 /*************************************************************
633 * Module support routines
634 *************************************************************/
639 int answer = ppp_register_compressor (&ppp_deflate);
642 "PPP Deflate Compression module registered\n");
651 "Deflate Compression module busy, remove delayed\n");
653 ppp_unregister_compressor (&ppp_deflate);